Netaji Subash chandra Bose played a Big role by Forming Indian National Army and created pressure on British but why is he still a Forgotten hero?
Could it be that his sympathies for and open association with one of the most hated government doctrines of the 20th century overshadowed his strive for Indian independence?
He may have wanted to accomplish something that we now see as good, but he tried getting there with the help of Nazi Germany. That is a very effective way to (internationally) be seen as "not a good guy" after 1945.
Even today, more than 70 years after the end of WWII, politicians try to avoid being associated with the national socialism and fascism, even if some of them do share some ideas with those ideologies.
One could ask why Hitler is not widely credited and respected for making life in most of Europe easier by introducing the same time-zone for most of the European mainland. Sure, I think it is a very practical thing, and many people like the result. However, dragging the world into a bloody war and (even more importantly) trying to exterminate a complete people are the kind of things that make people forget whether you did anything positive.
Netaji Subash Chandra Bose played a bigger role in India's Independence ...
That is actually not true. According to Wikipedia,
The British Raj, though never seriously threatened by the INA, charged 300 INA officers with treason in the INA trials, but eventually backtracked in the face both of popular sentiment and of its own end.
So, even though he was a great leader, he actually wasted a lot of time contacting German and Japanese authorities to get Indian soldiers freed, and in the end, his initiative achieved nothing.
... but still, he is a forgotten hero why?
His political decision was not compatible with Congress, and hence had a spat with Nehru or Gandhi. According to Wikipedia,
Indian National Congress, the main instrument of Indian nationalism, praised Bose's patriotism but distanced itself from his tactics and ideology, especially his collaboration with Fascism.
Also, he died very early, even before the independence of India.